Blackboard illusion device.



G. F. DE GRASSE.

BLAGKBOARD ILLUSION DEVICE.

APPLICATION FILED FEB.13, 1913.

Patented Oct. 21, 1913.

INVENTOR WITNESSES.-

A llorneys some character on GEORGE FELIX QB YQBIKQN. Y;

Application filed February 13, 1913.

To all whom it may'concera:

Beitknown that LGnonoc FELIX DE GRASSE, a citizcn'oftheUnited States, residing inthe city of New York, borough of Brooklyn, county of Kings, and State of New York, have invented a certain new and useful- Blackboard Illusion Device, of which the following is a specification.

This invention: is'ablackboard illusion device, and the object thereof is to enable an entertainer to draw or sketch an object of the board, and thereafter to illusion the audience into believing'that saidsketches may be utilized to'perform' the functions of the objects which they represent.-

In one, and the preferred, practical embodiment of the invention, the entertainer, in the presence of the audience, draws a chair and table on the board, 6. with chalk, whereupon, preferably by the aid of an accomplice, he apparently seats himself upon the chair, with his feet comfortably resting on the table.

The chair andtable', sketched as described, are enabled to perform their apparent functions, by means of weight sustaining. devices, which, after the sketches are made, are; at the proper moment, surreptitiously projected forwardly from the face of the board, preferably by the assistance of a concealed accomplice, the said weight devices being, of course, properly positioned to suport the entertainer in the desired position.

In the accompanying drawings, I have illustrated one practical embodiment of the invention, but the construction shown therein is to be understood as illustrative, only, and not as defining the limits of the invention.

Figure 1 is a view showing the stationary and movable parts of the device of the present invention in perspective. Fig. 2 is a vertical section taken on line 2-2 of Fig. 3. Fig. 3 is a front elevation showing how the device of the present invention appears to the audience.

In said drawings, A indicates a blackboard having suitable means, such as the end pieces a, (2, whereby sufficient base is provided to retain the board in upright position. The board is apertured at b, b, 19 to allow for the projection of the several arms or pipes c,c,0- of the supporting member C therethrough. This supporting mem- Specification of Letters Patent.

'ished: the sketches,

arms of the supporting member BLA'GKBOARD ILLUSION DEVICE.

PatentedOct. 21-, 1913.

Serial No. 748,056.

ber G ispreferably fixedly mounted on a movable carriage D in any suit-able manner, as by the securing devices 0Z-,it being understood that said supporting member is so positioned with respect to theapertures in the blackboard, that, when thecarriage-is'moved into close proximity with said board, the arms, 0, a, 0 will register with, and projectwthrou'gh, their respective apertures 12, 9

The following is illustrative: of thermanner in which the device is employed in entertaining theatergoers. Previous to: the raising of the curtaimthe blackboard A and the carriage D are so positioned on the stage, that the board will: face the audience, and its end pieces or wings a, a, will fully conceal thecarriage which is positioned just in rear thereof. A stageh'and. having secreted himself-behind the carriage, the curtain rises, and the entertainer walks out upon the stage,- and, picking: up a piece of chalk, quickly sketches an object, or objects-on: the blackboard,v as,-e. 9., the chair E and the table F, shown. Having fin the artist turns, picksup a paper, bows to he audience and, giving a signal to his confederate secreted behind the device, proceedsto seat himself on the chair which he'has sketched The confederate is inreadiness for this signal, so that, by the time the entertainer is ready to seat himself, he (the accomplice) has pushed the carriage forward, thereby projecting the through the apertures in the blackboard. This having been done, the artist apparently seats himself in the chair with his feet resting on the table, as shown in Fig. 3. In reality, however, he is sitting on the arm or pipe 0', resting his back against the pipe 0, while the pipe 0 supports his feet. After the lapse of a few minutes, during which the audience is held in suspense, the entertainer, having given a signal to the accomplice, slowly lifts his feet off the table, and rises to a standing posture, whereupon the accomplice withdraws the carriage and the supporting arms, and the deception is com lete.

It will be manifest that, to obtain the best results, the arms of the member 0, which project through the apertures in the board, should closely match, in color, the background which they will have when projectbeyond the surface of the board, for the ing reason that any difference in color would allow the outlines of said arms to be discerned, and the illusion would fail.

Although I have hereinbefore shown and described one embodiment of the present invention, I wish it clearly understood that this form is illustrative, only, and that there are numerous ways in which the spirit of the invention might be carried out; e. 9., instead of sketching on a blackboard with chalk, the board might be any color, and paper patterns, cut to represent articles, might be placed on said board. Moreover, the specific construction of the device might be varied to suit the taste of the entertainer; e. 9., the carriage might be omitted and the supporting devices manipulated so as to be readily pushed through the apertures in the board. Furthermore, if desired, it is obvious that, instead of having an accomplice for projecting the supporting devices, this could be done mechanically. Moreover, the performance of the to one individual, since several individuals, or even one or more animals, may, under certain conditions, participate in it. However performed, it will be'obvious that the act is an instructive and pleasing illusion.

Having thus fully described the invention, what I claim as new, and desire to secure by Letters Patent is 1. An illusion device embodying a surface on which suitable objects may be designated, and means cooperating with said surface whereby said designated objects are made to appear to perform the functions of the real objects which they represent.

2. An illusion device embodying a sur face onwhich suitable objects may be designated, and weight sustaining devices cooperating with said surface whereby said designated objects are made to appear to erating therewith act need'not be limited for apparently enabling the sketched objects.

to perform the functions of the real objects which they represen 4. An illusion device embodying a blackboard on which certain objects may be drawn, and weight sustaining devices 006pfor apparently enabling the sketched objects to perform the functions of sent.

5. An illusion device embodying a blackboard on which certain objects may be drawn, and weight sustainingmembers-concealed rearwardly of the board and adapted to be surreptitiously projected forwardly of the board so as to sustain the weight of a performer, thereby apparently enabling the performer to use the objects drawn on the board as though employing the real objects represented.

6. An illusion device embodying an apertured blackboard on which objects may be designated, a carriage movable toward and away from said blackboard, and weight supporting arms fixedly mounted on the carriage and adapted to cooperate with the apertures in the blackboard, whereby the objects designated. on the blackboard are made to appear to perform the functions of the real objects they represent.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

GEORGE FELIX DE GRAS'SE. Witnesses:

JOSEPH A. RAACH,

W. T. GILLIAM.

Copies 01' this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

. Washington, .D. O.

the real objects which they repre- 

